1. Technical Field
The present invention relates to a cutting device and to a printer having a cutting device that cuts paper or other medium placed or passed between the cutting edges of a fixed knife and a movable knife by moving the movable knife to the fixed knife and sliding the cutting edge of the movable knife along the cutting edge of the fixed knife.
2. Related Art
Printers that print on continuous paper such as roll paper or label paper often have a cutting device for cutting off the printed portion of the paper. The cutting device is located at the downstream end of the transportation path that goes to the paper exit passed the printing position of the print head (that is, near the paper exit), and the cut-off portion of the paper is discharged from the paper exit. Such cutting devices include scissor cutters that cause the movable knife to pivot to and away from the fixed knife, and sliding cutters that move the movable knife bidirectionally in a straight line to and away from the fixed knife.
A printer having a cutting device is taught in Japan Patent No. 3800891. The cutting device used in said printer has a fixed knife that is disposed on the printer frame side, and a movable knife that is disposed on the main cover side. When this cover is closed, the movable knife is set to a position opposite the fixed knife with the transportation path therebetween, and is configured to move freely bidirectionally relative to the fixed knife and cut paper in cooperation with the fixed knife. The cutting device also has a drive means that causes the movable knife to move bidirectionally.
When the movable knife cuts the paper while moving to the fixed knife side in a cutting device having a movable knife and a fixed knife on opposite sides of the transportation path for conveying the paper as described above, the leading end in the transportation direction of the paper that is left in the printer (that is, the end of the paper on the side that was not cut off and becomes the leading end after the paper is cut) may also be carried with the movement of the movable knife in the direction of movable knife movement and be left in contact with the fixed knife instead of returning to its original position. When cutting is finished and the movable knife then returns to its home position, the end of the paper that should be positioned in the transportation path may remain in contact with the fixed knife. If the paper is then advanced from this position for printing, for example, paper transportation will start with the end of the paper outside of the transportation path and touching the fixed knife. The paper will therefore not be conveyed through the transportation path and a paper jam or other paper conveyance problem may result.
It is also possible to reverse the paper after cutting so that the leading end of the paper separates from contact with the fixed knife. However, if the paper is thus reversed, the curled end of the paper may arch and contact the print head, thus possibly soiling the paper or adversely affecting the print head. Controlling returning the paper to the original position when the paper is retracted after cutting is also complicated, is time-consuming, and adding such control increases the cost.